Charging systems for the battery system of a vehicle use an inductive and/or conductive connection to connect the battery system of the vehicle to a mains connection point or to another current source of an infrastructure for charging the battery system. The inductive connection uses a transmitter coil and a receiver coil for the electromagnetic transmission of energy in the charging process. The conductive connection uses a wired connection, that is to say a cable, to transmit energy in the charging process. The battery system comprises secondary battery cells, that is to say accumulator cells, which are charged by the charging system.
If charging is provided by way of inductive and conductive charging systems in a vehicle, two different electrical connections to the battery system are provided in the vehicle. Firstly, the transmitter coil of the inductive charging system is connected to the battery system via a rectifier and a filter. Secondly, a socket for the cable is connected to the battery system via a further rectifier, a power factor correction element and a DC voltage converter (DC-to-DC converter).
Current inductive charging systems generate a DC voltage from the 50 Hz or 60 Hz mains voltage by way of rectification, PFC and smoothing. The DC voltage is generated in a DC current intermediate circuit. The DC voltage feeds a high-frequency inverter for supplying the transmitter coil (primary coil). The high-frequency AC voltage at the output of the receiver coil (secondary coil) is rectified and smoothed in the vehicle. In inductive charging systems that are supplied both in single-phase mode and in multiphase mode, additional components are required in the infrastructure for PFC and smoothing, since otherwise the voltage induced in the secondary coil would pulse. These components increase complexity and costs.
FR 02981521 A1, US 2013207601 A1, US 2014265615 A1, US 2014340027 A1 and US 2015311723 A1 disclose inductive charging systems for charging a vehicle battery, in which a DC voltage is generated from the mains voltage by way of rectification and power factor correction, PFC.